The above program demonstrates how easy it is to combine addstr
and move to print at a specific location on the screen. It
also shows how to use the equivalent key parameters #:y and
#:x. They do exactly the same thing. It also shows how
(format #f …) can be used in conjunction with addstr
to do formatted output.

The example introduces the new function getmaxyx. It gives the
number of columns and the number of rows in a given window.
getmaxyx does this by returning a list of two elements,
y and x.